Back to the Future

"What the actual fuck?" Katsuki growled, looking - glaring - up at the number four Pro Hero expectantly. "Is this," he said pointing to the leech currently clinging to his leg with distaste "why you called me back mid-patrol?" Best Jeanist didn't even have the chance to answer before Katsuki was shaking his leg, "Let go." he said sharply, the girl only clutched him harder. "And why the fuck is she calling me daddy?" (Or: Katsuki and Izuku's daughter comes from the future and Katsuki is determined to keep Deku from finding out she is also his, lest she reveal his true feelings for him. But at what price is he willing to keep it that way?)